Heat oil in a sauce pan and saute the grated garlic and ginger.

Pour orange juice in the pan and give it a mix.

Add lemon juice, lemon zest, dark soy sauce, rice vinegar, cayenne powder and season it with salt and pepper.

Let it simmer for about 10 minutes.

Mix corn flour with the water and pour it in the sauce pan. This will thicken the sauce.

Add sugar and keep stirring for another few minutes.

Check for salt and add more, if needed.

Switch off the heat and keep the sauce aside.

Clean the shrimp and pat dry it with a kitchen towel or tissue paper.

In a plate, mix flour with rest of the ingredients except shrimp and oil.

Drop the shrimps on the plate and mix it with the flour.

Heat enough oil in a wok to deep fry the shrimps. If you want to avoid deep frying, you could always pan fry it with less oil.

Remove the shrimps from the flour mix and drop it carefully in the hot oil.

Fry them till they are golden brown. It should take about 4 to 5 minutes. Avoid crowding the pan by dropping too many shrimps at a time. 

Once done, keep the shrimps in a kitchen towel or tissue paper to remove the excess oil.

In a separate pan, heat some oil and saute the onions till they are golden brown in color.

Put the shrimp and mix it properly with the onions.

Pour the sauce in the pan and give it a good mix. You may add all the sauce or some of it, depending on how you wish to serve it. I kept some sauce aside to add it later, if needed. 

Add ½ cup water and let it simmer for 5 minutes.

Garnish it with some fresh cilantro leaves and serve it hot.